Truck platooning, connecting a chain of computer-controlled trucks electronically to follow a human-driven lead vehicle, is still at least 5 years away from being used commercially, but the next step in freight transport automation is already coming over the horizon. Earlier this month Nevada authorized the testing of self-driving trucks on the state’s highways.

Daimler, the first company to receive approval to test self-driving trucks in the state, has previously operated its autonomous trucks on a closed section of Germany’s autobahn, where they underwent 10,000 miles of testing. The trucks being tested in Nevada will still require the oversight of a human driver in the vehicle during operation, and human intervention is needed for maneuvers such as changing lanes to pass and operating on local streets. But the company envisions that during the hours of freeway operation the driver will be able to work on other tasks, such as billing and itinerary planning, while the truck drives itself.

However, with the role of human truck drivers shrinking, it may not be long before they are out of the loop altogether. In 2014 the U.S. military conducted a series of successful tests of fully automated truck convoys following a driverless lead vehicle.

While the possibility of eliminating human error behind the wheel is one of the biggest selling points for self-driving trucks, uncertainty about who would be liable for crashes caused by self-driving vehicles remains an obstacle to widespread adoption.